When I joined here I was considering doing the carbon dioxide method. As people have mentioned it is usually peaceful and you can die in your sleep, but have to do it in a very closed area to succeed. But I also realized it was a very time consuming method compared to SN for me. I would have had to buy a tent, bucket, chimney starter, coal. And I'd have to prepare it outside late at night while my family is asleep. What if they see me? Anyone could wake up in the middle of the night and look out the window and catch me.
I switched to SN as it is another peaceful method, and you fall asleep and die quickly, etc. Not only that, but I can do it much more discreetly. I won't have to go out or set anything up besides taking pills and mixing SN into the water. There was no way I could get my hands on N, so I've settled with SN. It is very affordable and that is why many people have chose this method.